The present disclosure relates to an information processing device, an information processing method, and a program. More specifically, the present disclosure relates to an information processing device, an information processing method, and a program, which enable source tracing of illegally distributed content and prevention of illegal use of content.
A digital versatile disc (DVD) or a Blu-ray (registered trademark) disc (BD) has been widely used as an information recording medium (media) that records various types of content such as movies and music.
Creators and distributors own copyrights and distribution rights for many types of content such as music data and image data which are recorded on the information recording medium. Accordingly, it is general to perform use control so as to allow only users with legitimate rights to use the content, when content stored on such an information recording medium (media) is provided to the users.
Specifically, for example, control is performed such that content is recorded as encrypted content, and the content can be decrypted by only an encryption key which has been provided to the users who has performed a legitimate content purchase process. However, even after such a process, for example, if the user who has encrypted content illegally distributes or publishes the decrypted content or the encryption key, unauthorized use of the content by many unspecified people occurs. Thus, in recent years, unauthorized publication or distribution of data is frequently performed through a network, and thus there is a major problem of preventing the unauthorized publication or distribution.
As a measure for preventing the unauthorized distribution of content, there is a configuration of enabling discrimination of a device that has performed a decryption process based on decrypted (plaintext) content.
It is configured to analyze decrypted content, for example, decrypted image data which is generated by decrypting encrypted content, and discriminate a device that has performed the decryption process, based on identification data extracted from an image.
A configuration enabling the source tracing is described in, for example, Japanese Unexamined Patent Application Publication No. 2007-43336.
In the configuration described in Japanese Unexamined Patent Application Publication No. 2007-43336, content is configured as a segment which is configuration data, for example, an image of a certain scene constituting movie content is configured as a plurality of pieces of variation data which can be decrypted by different keys. Each playback device selects and decrypts one piece of data which can be decrypted from a plurality of pieces of variation data by applying a playback device specific key which is stored in the playback device, and plays the image. The playback devices storing different keys decrypt different variation data for the image of the same scene and play the image. In this manner, different variation data is selected and played depending on each playback devices. In other words, a playback process is performed according to a different playback path depending on a playback device.
For example, when copy data of the decrypted content is distributed through a network, it is possible to identify a device that has decrypted the content, to some extent, by analyzing variation data and a playback path included in the content.
Further, encryption keys (decryption keys) stored in respective playback devices are different depending on manufacturers of devices, and it is possible to trace a source depending on the configuration units.
However, illegally copied content of which the source is not discriminated may be created by the following manner against the measure enabling the source tracing.
For example, one piece of content is generated by mixing two pieces of content configured with two different playback paths which are decrypted and played by two playback devices A and B.
For example, mixed content is configured in such a manner that the first part of the content is configured with a playback path corresponding to the playback device A which is decrypted by the playback device A and the second part of the content is configured with a playback path corresponding to the playback device B which is decrypted by the playback device B. When the mixed content is copied and spread on a network, it is difficult to trace a correct source from the copy content.